Core drill



Patented July 5, 1927.

SATES WALTER, C. BARNES, 0F TAFT, CALIFORNIA.

CORE DRILL.

Application filed June 23, 1926.

The present invention relates to improvements in core drills, and has for its principal object to provide a plug for the core bit of a drill whereby loose shale and sand or other formation will be prevented from entering the barrel of the drill until such time as the core is taken.

It frequently happens that in lowering a core drill into a well that the heavy "formations such as rock, sand and shale which has settled to the bottom of the hole will enter the core barrel and will pass through the barrel and the valve seat into the drill pipe -where the same becomes trapped.

Some of the particles are relatively large, and as a result cannot pass through the circulating holes provided in the core bit, and as a result they plug them and cause unnec. essary work. The purpose of the present invention is to provide an attachment for a core drill which will eliminate the above disadvantages.

Another important object of the invention is to provide a coredrill wherein the plug which is associated with the core bit may be released by the rotation of the barrel, additional means being associated with the plug for holding the same in one position while u the barrel is being rotated so as to remove the same from the plug.

A still further object is to provide a core.

drill of the above mentioned character which is simple in construction, inexpensive, strong and durable and further well adapted to the purpose for which it is designed.

Other objects and advantages of the invention will become apparent during the course of the following description taken in connection with the accompanying drawing.

In the accompanying drawing forming a part of this application and in which like numerals designate like parts throughout the several views Figure 1 is a vertical sectional view through the lower portion of a core drill showing my removable plug supported in the core bi Figure 2 is a side elevation of the plug per se, and

Figure 3 is a transverse sect-ion through the core bit and the lug.

In the drawing w erein for the purpose of illustration is shown the preferred embodiment of my invention, the numeral 1 designates the inner barrel. of a core drill,

Serial No. 118,026.

the outer barrel being designated enera-lly by the numeral 2. The core bit is esignated generally by the numeral 3, the same comprising the tubular body portion 4, the upper end of which is provided with .the enlarged internally threaded portion 5 for engagement with the externally threaded lower end of the outer pipe 2 in the manner clearly shown in Figure 1. The intermediatepob tion of the tubular body t is threaded on the lower threaded end of the inner barrel 1 as indicated at 6.

The exterior lower portion of the core bit 3 is slightly rounded and extending laterally therefrom are the cutting wings or blades 7. As the construction of the core bit is well known in the art, a further description thereof is thought unnecessary. The lower portion of the hit 3 is provided with the internally threaded portion 8 and the purpose thereof will be presently apparent.

A cylindrical plug 9 is adapted to be removably fitted in the lower portion of the bit 3 and for the purpose of holding the plug in the lower portion of the bit, said plug is externally threaded at a point adjacent its upper end as indicated at 10, and this threaded portion cooperates with the internally threaded portion 8 of the lower por-' tion of the bit 3 in the manner clearly shown in Figure 1. The plug 9 is adapted to provide a closure for the lower end of the inner barrel 1 so that the loose shale, sand or other formation will be prevented from entering the barrel, while the core drill is in use. The

plug 9 is further tapered at its top as indi-' cated at 11 to prevent the plug from catching on the core attacher springs 12 which are arranged within the core bit 3 in the manner also well known inthe art.

The plug 9 is of such length as to have its lower portion extending below the cutting wings or-blades 7, and the lower end of the plug 9 is slightly rounded on its opposite sides as illustrated at 13 to form a continuation of the rounded exterior .portion of the bit 3. The outwardly projecting lower end portion 13 of the plug 9 has formed thereon the ground engaging portion 14, the same being preferably in the form of a chisel- The plug 9 is further provided with longitudinally extending fluid passages 15, the same extending from the rounded bottom 13 of the plug to the top thereof to PIOYlLle a means whereby the plug will be permitted to enter the inner barrel 1.

it will thus be seen from the foregoing description, that I have provided an attachment for a core drill which will provide a closure for the lower open end of the inner barrel thus preventing any possibility of any foreign substance entering the barrel while the drill is in use. The simplicity in which the plug is constructed enables the same to be readily inserted or removed with respect to the core bit and Will not in any way interfere with the operation of the core drill and the bit.

While I have shown the preferred exnbodiment of the invention it is to be understood that minor changes in the size, shape and arrangement of parts may be resorted to Without departing from the spirit of the invention and the scope of the appended claim.

Having thus described the invention, What l claim as new and desire to secure by Letters Patent is:-

in a core drill, an inner barrel, a. casing surrounding the same, a core bit secured on the lower end thereol said bit being provided with the usual laterally extending blade and core attacher spring, a. removable solid plug threaded in the bit to provide a slosure for the lower end of the innerbarrel, the upper end of the plug being beveled, the lower end 01 the plug extending beyond the bottom oi the bit and being shaped to form a continuation of the lower exterior portion of the bit, a ground engaging element formed on the lower end of the plug itor preventing the rotation thereof in order to facilitate the removal of the .corebit from the plug, said plan; being provided with longitudinally extending passages to permit a fluid to enter the inner barrel.

In testimony whereof I allix my signature.

WALTER G. BARNES. 

